The enzymatic properties of the dextransucrase and levansucrase and the chemical nature of the dextrans and levans will be studied in this project. The primary emphasis of the structural work will be directed toward the insoluble dextrans elaborated by the cariogenic streptococci grown on sucrose. The enzymology of the sucrases will be studied to determine how pH affects the polymerization sucrose, origin of the branching, effect of metaphosphates and other inhibitors, etc. Sucrose analogs will also be prepared that will inhibit the sucrase and, hopefully, not be toxic to humans.